/* 全局样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* 定义主题色 */
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --accent-color: #e74c3c;
    --light-color: #ecf0f1;
    --dark-color: #34495e;
    --card-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
    --transition: all 0.3s ease;
}

body {
    font-family: "Segoe UI", "Microsoft YaHei", sans-serif;
    line-height: 1.7;
    color: var(--dark-color);
    background-color: #f8f9fa;
    background-image: 
        radial-gradient(var(--light-color) 2px, transparent 2px),
        radial-gradient(var(--light-color) 2px, transparent 2px);
    background-size: 40px 40px;
    background-position: 0 0, 20px 20px;
    padding-bottom: 50px;
}

/* 头部样式 */
header {
    background: linear-gradient(135deg, var(--primary-color), var(--dark-color));
    color: white;
    padding: 3rem 0;
    position: relative;
    overflow: hidden;
    text-align: center;
}

header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.1'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
    opacity: 0.3;
}

header h1 {
    font-size: 2.8rem;
    margin-bottom: 1rem;
    position: relative;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
}

nav {
    position: relative;
}

nav ul {
    list-style: none;
    display: flex;
    justify-content: center;
    gap: 2.5rem;
    margin-top: 1.5rem;
}

nav a {
    color: white;
    text-decoration: none;
    font-weight: 600;
    font-size: 1.1rem;
    padding: 0.5rem 0;
    position: relative;
    transition: var(--transition);
}

nav a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--secondary-color);
    transition: var(--transition);
}

nav a:hover {
    color: var(--secondary-color);
}

nav a:hover::after {
    width: 100%;
}

/* 主要内容区域 */
main {
    max-width: 1200px;
    margin: 3rem auto;
    padding: 0 1.5rem;
}

section {
    background-color: white;
    border-radius: 12px;
    padding: 2.5rem;
    margin-bottom: 3rem;
    box-shadow: var(--card-shadow);
    transition: var(--transition);
    position: relative;
}

section:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.1);
}

section h2 {
    font-size: 2rem;
    color: var(--primary-color);
    margin-bottom: 1.8rem;
    padding-bottom: 0.8rem;
    border-bottom: 3px solid var(--secondary-color);
    display: inline-block;
    position: relative;
}

section h2::after {
    content: '';
    position: absolute;
    width: 50%;
    height: 3px;
    background-color: var(--accent-color);
    bottom: -3px;
    left: 0;
}

/* 团队介绍 */
.team-members {
    display: flex;
    flex-wrap: wrap;
    gap: 2rem;
    justify-content: center;
}

.team-member {
    background-color: white;
    border-radius: 10px;
    width: 200px;
    padding: 1.8rem 1.2rem;
    text-align: center;
    box-shadow: var(--card-shadow);
    transition: var(--transition);
    border-top: 4px solid var(--secondary-color);
}

.team-member:hover {
    transform: translateY(-8px) scale(1.02);
    box-shadow: 0 10px 20px rgba(52, 152, 219, 0.15);
}

.team-member h3 {
    font-size: 1.3rem;
    color: var(--primary-color);
    margin-bottom: 0.6rem;
}

.team-member p {
    color: var(--dark-color);
    background-color: var(--light-color);
    padding: 0.5rem 0;
    border-radius: 6px;
    font-weight: 500;
}

/* 项目介绍 */
#project p {
    font-size: 1.1rem;
    margin-bottom: 1.2rem;
    line-height: 1.8;
}

#project p:last-child {
    margin-bottom: 0;
}

/* 实习日志 */
.log-container {
    position: relative;
}

/* 时间轴效果 */
.log-container::before {
    content: '';
    position: absolute;
    top: 0;
    bottom: 0;
    left: 30px;
    width: 4px;
    background-color: var(--secondary-color);
    border-radius: 2px;
}

.log-entry {
    background-color: white;
    border-radius: 10px;
    padding: 1.8rem;
    margin-bottom: 2.5rem;
    box-shadow: var(--card-shadow);
    transition: var(--transition);
    padding-left: 2.5rem;
    position: relative;
}

.log-entry::before {
    content: '';
    position: absolute;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background-color: var(--accent-color);
    left: -12px;
    top: 2.2rem;
    border: 4px solid white;
    z-index: 1;
}

.log-entry:hover {
    transform: translateX(8px);
    box-shadow: 0 8px 15px rgba(0, 0, 0, 0.1);
}

.log-entry h3 {
    font-size: 1.6rem;
    color: var(--primary-color);
    margin-bottom: 0.6rem;
    display: flex;
    align-items: center;
}

.log-entry h3::before {
    content: '';
    display: inline-block;
    width: 8px;
    height: 8px;
    background-color: var(--accent-color);
    border-radius: 50%;
    margin-right: 10px;
}

.log-date {
    color: var(--secondary-color);
    font-weight: 500;
    margin-bottom: 1.2rem;
    font-size: 1rem;
    display: block;
    letter-spacing: 0.5px;
}

.log-entry p {
    margin-bottom: 1rem;
    line-height: 1.8;
}

.log-entry p:last-child {
    margin-bottom: 0;
}

/* 页脚样式 */
footer {
    background-color: var(--primary-color);
    color: white;
    text-align: center;
    padding: 2rem 0;
    margin-top: 5rem;
    position: relative;
}

footer::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 10px;
    background: linear-gradient(90deg, var(--secondary-color), var(--accent-color));
}

footer p {
    font-size: 1.1rem;
    opacity: 0.9;
}

/* 响应式设计 */
@media (max-width: 768px) {
    header h1 {
        font-size: 2.2rem;
    }

    section {
        padding: 1.8rem;
    }

    section h2 {
        font-size: 1.7rem;
    }

    .log-container::before {
        left: 20px;
    }

    .log-entry {
        padding-left: 1.5rem;
    }

    .log-entry::before {
        left: 8px;
    }

    .team-members {
        gap: 1.5rem;
    }

    .team-member {
        width: 160px;
    }
}

@media (max-width: 480px) {
    nav ul {
        gap: 1.5rem;
    }

    nav a {
        font-size: 1rem;
    }

    .log-entry h3 {
        font-size: 1.4rem;
    }
}